More boisterous argument with the German and Republican (7)
I believe the answer is:
rowdier
'more boisterous' is the definition.
'argument with the german and republican' is the wordplay.
'argument' becomes 'row' (I've seen this before).
'with' means one lot of letters go next to another.
'the german' becomes 'die' ('the' in German).
'and' means one lot of letters go next to another.
'republican' becomes 'r' (abbreviation).
'row'+'die'+'r'='ROWDIER'
(Other definitions for rowdier that I've seen before include ""noisier"" , "more disturbing" , "More raucous" , "more noisy" .)